If \( f(x) = \begin{cases}
\frac{x^2 + 3x - 10}{x^2 + 2x - 15}, & x \neq -5 \\
a, & x = -5
\end{cases} \) is continuous at \( x = -5 \), then the value of \( a \) will be
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To determine the value of \( a \) for continuity, solve the limit of the function as \( x \) approaches the point.